The present invention relates to fiberoptic devices and, more particularly, to optical isolators useful in allowing the transmission of light signals in one direction along an optical fiber and blocking the transmission of light signals in the opposite direction.
In present day optical fiber technology, it is often very useful for light signals to move only in one direction along an optical fiber. For example, semiconductor lasers are typically used to generate and to relay light signals on optical fibers. These lasers are particularly susceptible to light signal reflections, which can cause a laser to become unstable and noisy. Optical isolators are used to block these reflected signals from reaching the laser. Ideally, an optical isolator transmits all of the light signals in the forward direction and blocks all of the signals in the reverse direction.
Of course, optical isolators do not attain ideal performance levels and improvements are constantly sought. Furthermore, lowered manufacturing costs are desirable to encourage the spread of optical fiber networks with their inherently large bandwidths. With an optical isolator generally required for each laser generating signals on an optical fiber, it is beneficial that the cost of the optical isolators be lowered as much as possible. Finally, for ease of installation, reliability and low material costs, a small size for optical isolators are desirable also.
The present invention substantially meets those goals by offering a miniaturized optical isolator having a high performance. The optical isolator is capable of being manufactured at lowered costs.